O'Malley agreed to a minor-league contract with the Rockies on Saturday which includes an invitation to spring training, Bob Dutton of The Tacoma News Tribune reports.
O'Malley missed the majority of the 2017 season while recovering from an appendectomy and arthroscopic shoulder surgery. He ended up appearing in 33 games across three levels of the minors, but hit just .235/.333/.361 over that span before being cast off the Mariners' 40-man roster in September. He'll look to catch on as a utility man, though it's more likely he winds up as organizational depth.